—The authors thank Dr Holdiness for his comment. The primary intent of our article was to emphasize pharmacokinetic drug interactions with rifampin therapy that occurred with commonly prescribed agents used in the United States. Drugs administered concomitantly with rifampin, which caused an increase in adverse effects such as hepatitis, was not the major focus of this article. Additionally, the thioamides used as second-line antituberculosis agents and, as antileprosy agents are not widely prescribed in the United States. Further pharmacokinetic and adverse drug interactions should be expected for rifampin therapy.